This invention relates generally to a novel method and apparatus for insulating the interior of a high temperature chamber or furnace. More particularly, this invention is concerned with minimizing the deleterious effects of a highly corrosive atmosphere in an industrial furnace on an insulation lining attached to the internal walls of the furnace.
In the past, it is been known to line the interior of high temperature chambers or furnaces with ceramic fiber insulation material manufactured into modules. See for example U.S. Pat. Nos. 3,819,468; 3,993,237; 3,706,870; 4,154,975; 3,940,244; 4,032,742; and 4,177,036, all of which are assigned to the assignee of the present application, Sauder Industries, Inc., Emporia, Kans. These patents relate to high temperature ceramic fiber insulation modules capable of insulating furnaces having interior temperatures in excess of 2300.degree. F. By "high temperature", applicant means temperatures in excess of 1600.degree. F. and more particularly temperatures falling in the range of 1600.degree. F. to 2800.degree. F.
The modules disclosed in the above-noted patents have been very successful in insulating furnaces wherein it is desirable to maintain a casing temperature of the furnace in the order of 200.degree. F. to 300.degree. F. or even cooler while at the same time generating a high temperature environment within the interior chamber of the furnace. Furnaces insulated with the above-noted products have performed most satisfactorily. Whereas known arrangements have exhibited a satisfactory level of utility in insulating high temperature chambers, room for significant improvement remains.
It is believed that in environments containing highly corrosive gases, for example, those containing sulfur compounds, it is common to experience a corrosive action on metallic fastening hardware or support substrates. Whereas the ceramic fibers of the insulation material exposed to such a chemically hostile environment remain substantially unaffected, the fastening hardware or support substrate or the cement bonding the fiber to the substrate may deteriorate to such an extent that the structural integrity of the insulation material is threatened.
Particular problems have been noted in instances where sulfur containing gases have been generated in furnace chambers and have penetrated the ceramic insulation material into the cooler regions of the furnace. In these cooler regions, usually along the surface of the cold face of the insulation material, the sulfur containing gases condense together with some water vapor to produce a relatively strong concentration of acid. The effects of sulphur containing acids on metal are well known.
Most recently it has been discovered that sulfur containing acids may have an adverse effect over a period of 6 to 18 months on ceramic mortars, or even to ceramic fiber itself where such contact is prolonged.
Recognizing the need for an improved method and apparatus for insulating the interior chamber of a high temperature furnace, it would, therefore, be desirable to provide a high temperature industrial furnace module which may be easily installed and which minimizes the undesirable effects of a corrosive atmosphere on the support structure and attachment mechanism of such module.
The problem stated in the foregoing is not intended to be exhaustive but rather is among others which tend to impair the effectiveness of previously known insulation modules used in conjunction with high temperature furnaces operating in a highly corrosive atmosphere.